This invention relates to compositions and methods which enhance membrane permeability of negatively charged polymers, such as RNA and DNA.
Negatively charged polymers, such as nucleic acid, can be introduced into a cell by a variety of procedures including microinjection, electroporation, and liposome fusion. For example, liposomes made from LIPOFECTIN.TM. can be used to introduce nucleic acid into eukaryotic cells. Eppstein et al., U.S. Pat. No. 5,208,036 (1993). LIPOFECTIN.TM. contains an amphipathic molecule having a positively charged choline head group (water soluble) attached to a diacyl glycerol group (water insoluble). Promega (Wisconsin) markets another cationic lipid, TRANSFECTAM.TM., which can help introduce nucleic acid into a cell.
Wagner et al., 88 Proc. Nat. Acad. Sci. USA 4255, 1991, Cotten et al., 87 Proc. Nat. Acad. Sci. USA 4033, 1990, Zenke et al., 87 Proc. Nat. Acad. Sci. USA 3655, 1990, and Wagner et al., 87 Proc. Nat. Acad. Sci. USA 3410, 1990, describe transferrin-polycation conjugates which may include DNA and enhance uptake of that DNA into cells. They also describe receptor-mediated endocytosis of transferrin-polycation conjugates to introduce DNA into hematopoietic cells.
Wu et al., 266 J. Bio. Chem. 14338, 1991, describe in vivo receptor-mediated gene delivery in which an asialoglycoprotein-polycation conjugate consisting of asialoorosomucoid is coupled to poly-L-lysine. A soluble DNA complex was formed capable of specifically targeting hepatocytes via asialoglycoprotein receptors present on the cells.
Biospan Corporation WO91/18012 describe cell internalizable covalently bonded conjugates having an "intracellularly cleavable linkage" such as a "disulfide cleavable linkage" or an enzyme labile ester linkage.